1. Field of the Invention
The present invention relate to an optical fiber connector for connecting optical fiber cables, and more particularly, to an optical fiber connector for connecting optical fiber cables each composed of a cable core comprised of a core and a cladding, an inner coating layer, and an outer coating layer.
2. Description of the Related Art
FIG. 1 is a view showing a mode in which an optical fiber cable C is inserted into an optical fiber connector of a prior art, FIGS. 2 and 3 are cross-sectional views showing how the optical fiber is assembled, and FIG. 4 is a cross-sectional view of the optical fiber cable when assembled. As shown in the figures, the optical fiber cable C consists of a cable core E comprised of a core and a cladding, both made of silica based glass, an inner coating layer P coated on the cable core E, and an outer coating layer S coated on the inner coating layer P. When the cable core E is a single mode optical fiber, a diameter of the core having a reflection index higher than that of the cladding is 10 .mu.m, and a diameter of the cladding is 125 .mu.m. The inner coating layer P is formed of a polyaramid fiber such as Kevlar (trademark of Du Pont Corporation), and the outer coating layer S is formed of PVC.
As shown in FIGS. 1 and 4, the cable core E of the optical fiber cable C is inserted into a ferrule F, a spring G is fitted over the cable core E and the ferrule F, a support H is fitted over the spring G, and a projection L of the support H is fitted into a fitting groove M of a plug hole K, to fix the support H thereat. Next, the inner coating layer P next to the cable core E is peeled back and then pulled forward and over a knurled portion N of the support H, a cylinder Q of a pinch member D is fitted over the portion of the inner coating layer P fitted over the knurled portion N and fastened thereat to sandwich the inner coating layer P between the pinch member D and the support H.
Then, as shown in FIG. 2, the outer coating layer S of the optical fiber cable C is fitted over a pinch portion R of the pinch member D, and as shown in FIG. 3, a cylinder T is fitted over the outer coating layer S and fastened from the outside as shown by arrows to sandwich the outer coating layer S between the cylinder T and the pinch member D, to thereby pinch-fasten the optical fiber cable C to the pinch member D.
As shown in FIG. 4, the pinch member D is inserted into an opening B of a connector cover A, made of an elastic material such as a rubber, and then a cap X is fitted over the connector cover A, to thus complete the connection of the optical fiber cable C to the optical fiber connector.
A stop edge W, having an inner diameter d.sub.2 which is smaller than an outer diameter d.sub.1 of the pinch member D, is provided at an insertion opening V of the opening B and projects inward to prevent an unintentional withdrawal of the pinch member D after it is inserted into the opening B of the connector cover A.
The prior art optical fiber connector, however, suffers from the following disadvantages. The provision of the stop edge W projected inward of the opening B requires the application of a strong pressure, to forcibly press the pinch member D into the opening B. The cover B, however, is formed of an elastic material such as a rubber, and accordingly, this forcible insertion of the pinch member D into the opening B is different and may damage an inner wall of the opening B. Namely, the prior art connection of the optical fiber cable to the optical fiber connector suffers from a low work efficiency, and requires a high level of skill. Accordingly, an automatic connection of the optical fiber cable to the optical fiber connector is practically impossible.